Carbon dioxide desulfurization system of urea device

Abstract

The invention discloses a urea device carbon dioxide desulfurization system, and relates to the technical field of feed gas desulfurization, the urea device carbon dioxide desulfurization system comprises a first desulfurization tower and a second desulfurization tower, the first desulfurization tower is composed of an upper tower I and a lower tower I which are fixedly mounted up and down, and the second desulfurization tower is composed of an upper tower II and a lower tower II which are fixedly mounted up and down. The communication mechanism is arranged between the first desulfurization tower and the second desulfurization tower, and the communication mechanism is used for coping with the fluctuation of the sulfur content in the carbon dioxide. By arranging the two desulfurization towers, sulfur in carbon dioxide gas is removed, a subsequent dehydrogenation catalyst is protected, the service life of the dehydrogenation catalyst is greatly prolonged, the dehydrogenation catalyst is usually precious metal, the investment is large, and a large amount of investment is saved when the service life is prolonged. Due to the parallel and series connection structure of the desulfurization tower, the operation is more flexible, and the fluctuation of the sulfur content in the carbon dioxide can be easily coped with.

Description

Technical Field

[0001] The invention belongs to the technical field of raw gas desulfurization, in particular to a carbon dioxide desulfurization system for a urea device. Background Art

[0002] The Chinese patent with the publication number CN209865697U discloses a CO2 raw gas desulfurization device in urea, including a pipeline body, a desulfurization bin, a discharge trough, a feed trough, a hinge and a fixed plate, a desulfurization bin is arranged inside the pipeline body, and a first isolation net and a second isolation net are fixed on the inner walls of the two sides of the desulfurization bin. The utility model drives the stirring rod to rotate by setting a reduction motor to stir the activated carbon particles, thereby improving the contact uniformity between the raw gas and the activated carbon particles and the efficiency of desulfurization. However, there are some defects in the use of the device. Since carbon dioxide is one of the raw materials of the urea device, the carbon dioxide pressure from the boundary area is low, and it needs to enter the urea synthesis device after being pressurized by a compressor. Before entering the urea synthesis device, carbon dioxide needs to be dehydrogenated. The catalyst used for dehydrogenation is currently sensitive to sulfur in the gas, which is easy to cause poisoning of the dehydrogenation catalyst, so carbon dioxide needs to be desulfurized before dehydrogenation. Moreover, the desulfurization catalyst powder cannot be processed, resulting in the desulfurization catalyst powder flowing with carbon dioxide, affecting the subsequent equipment work. Summary of the invention

[0003] The present invention aims to solve the technical problems existing in the prior art; to this end, the present invention proposes a carbon dioxide desulfurization system for a urea device.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A carbon dioxide desulfurization system for a urea device comprises a first desulfurization tower and a second desulfurization tower, wherein the first desulfurization tower consists of an upper tower 1 and a lower tower 1 fixedly installed vertically, and the second desulfurization tower consists of an upper tower 2 and a lower tower 2 fixedly installed vertically.

[0006] The connecting mechanism is arranged between the first desulfurization tower and the second desulfurization tower, and is used to cope with the fluctuation of the sulfur content in the carbon dioxide.

[0007] As a further solution of the present invention: the connecting mechanism includes a first conduit, a second conduit, a third conduit and a fourth conduit, the first conduit is arranged between the inlet pipe of the upper tower one and the inlet pipe of the lower tower two, the second conduit is arranged between the outlet pipe of the upper tower one and the inlet pipe of the lower tower two, the third conduit is arranged between the inlet pipe of the upper tower two and the inlet pipe of the lower tower one, and the fourth conduit is arranged between the outlet pipe of the upper tower two and the inlet pipe of the lower tower one.

[0008] As a further solution of the present invention: the upper tower 1, the lower tower 1, the upper tower 2 and the lower tower 2 are all provided with a differential pressure gauge, a feed pipe and a discharge pipe.

[0009] As a further solution of the present invention: a mixing mechanism is arranged on the upper tower 1, and a filter is arranged between the lower tower 1 and the lower tower 2.

[0010] As a further solution of the present invention: the mixing mechanism includes a fixed plate and a filter plate fixedly connected to the inside of the upper tower one, and a filter cartridge arranged on the outlet pipe of the upper tower one, the top of the fixed plate is fixedly connected to a motor, the output end of the motor is fixedly connected to a rotating shaft, one end of the rotating shaft passes through the fixed plate and the filter plate in sequence and extends to the bottom of the filter plate, a mixing plate is fixedly connected to the rotating shaft, the bottom of the filter plate is fixedly connected to a funnel, one end of the funnel passes through the upper tower one and extends to the outside of the upper tower one.

[0011] As a further solution of the present invention: one end of an outlet pipe of the upper tower passes through the funnel and extends to the interior of the funnel, and one end of an inlet pipe of the upper tower passes through the fixed plate and extends to below the fixed plate.

[0012] As a further solution of the present invention: a scraper is fixedly connected to the outer surface of the rotating shaft, and the bottom of the scraper is in contact with the bottom of the filter plate.

[0013] As a further solution of the present invention: a fixing frame is fixedly connected to the outer surface of the rotating shaft, a cleaning brush is fixedly connected to the fixing frame, the cleaning brush is fitted to the filter cartridge, and the fixing frame is fitted to the filter plate.

[0014] As a further solution of the present invention: the fixing plate is located above the feed pipe, and the filter plate is located below the discharge pipe.

[0015] As a further solution of the present invention: the first conduit, the second conduit, the third conduit and the fourth conduit are all provided with control valves, and an end cap is provided on one end of the funnel.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present application sets up two desulfurization towers to remove sulfur from carbon dioxide gas, protect the subsequent dehydrogenation catalyst, and greatly extend the service life of the dehydrogenation catalyst. The dehydrogenation catalyst is usually a precious metal, which requires a large investment. Extending the service life saves a lot of investment. The parallel and series structure of the desulfurization tower also makes the operation more flexible, and it is easy to cope with the fluctuation of the sulfur content in carbon dioxide.

[0018] (2) The present application adopts the configuration of upper and lower towers of the desulfurization tower, wherein the upper tower filler is activated carbon and the lower tower filler is zinc oxide. This configuration of first activated carbon and then zinc oxide greatly improves the desulfurization effect. In addition, the configuration of the upper and lower towers can also realize online replacement of fillers.

[0019] (3) The present application can improve the reaction between the catalyst and sulfur by utilizing a mixing mechanism, and can also process the catalyst powder at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a first perspective stereogram of the present invention;

[0021] Figure 2 It is a second viewing angle stereogram of the present invention;

[0022] Figure 3 It is a three-dimensional cross-sectional view of the upper tower 1 of the present invention;

[0023] Figure 4 It is a three-dimensional cross-sectional view of the funnel of the present invention.

[0024] In the figure: 1. first desulfurization tower; 1a. upper tower one; 1b. lower tower one; 2. second desulfurization tower; 2a. upper tower two; 2b. lower tower two; 3. connecting mechanism; 31. first conduit; 32. second conduit; 33. third conduit; 34. fourth conduit; 4. differential pressure gauge; 5. feed pipe; 6. discharge pipe; 7. mixing mechanism; 71. fixed plate; 72. filter plate; 73. filter cartridge; 74. motor; 75. rotating shaft; 76. mixing plate; 77. funnel; 8. filter; 9. scraper; 10. fixing frame; 11. cleaning brush. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1

[0027] See also Figure 1-3 As shown, the present application provides a carbon dioxide desulfurization system for a urea device, comprising a first desulfurization tower 1 and a second desulfurization tower 2, wherein the first desulfurization tower 1 consists of an upper tower 1a and a lower tower 1b fixedly installed up and down, and the second desulfurization tower 2 consists of an upper tower 2a and a lower tower 2b fixedly installed up and down; the upper tower 1a and the upper tower 2a are filled with activated carbon, and the lower tower 1b and the lower tower 2b are filled with zinc oxide.

[0028] The connecting mechanism 3 is arranged between the first desulfurization tower 1 and the second desulfurization tower 2, and the connecting mechanism 3 is used to cope with the fluctuation of the sulfur content in the carbon dioxide.

[0029] The connecting mechanism 3 includes a first conduit 31, a second conduit 32, a third conduit 33 and a fourth conduit 34. The first conduit 31 is arranged between the inlet pipe of the upper tower 1a and the inlet pipe of the lower tower 2b, the second conduit 32 is arranged between the outlet pipe of the upper tower 1a and the inlet pipe of the lower tower 2b, the third conduit 33 is arranged between the inlet pipe of the upper tower 2a and the inlet pipe of the lower tower 1b, and the fourth conduit 34 is arranged between the outlet pipe of the upper tower 2a and the inlet pipe of the lower tower 1b. The upper tower 1a and the upper tower 2a are filled with activated carbon, and the lower tower 1b and the lower tower 2b are filled with zinc oxide. The sulfur in the carbon dioxide gas is absorbed and converted by the catalyst. The entire desulfurization tower is connected in parallel or in series through the connection method of the first conduit 31, the second conduit 32, the third conduit 33 and the fourth conduit 34, and a differential pressure gauge 4 is provided to measure the inlet and outlet pressure difference of the desulfurization tower. When the pressure difference of the upper tower or the lower tower of one of the desulfurization towers increases to a certain extent, it is switched to the other desulfurization tower to work, and the desulfurization tower with the increased pressure difference is cut out of the system to replace the catalyst.

[0030] The upper tower 1a, lower tower 1b, upper tower 2a and lower tower 2b are all provided with a differential pressure gauge 4, a feed pipe 5 and a discharge pipe 6. The differential pressure gauge 4 can prompt the switching of the desulfurization tower and the replacement of the packing in time, thereby reducing the power consumption of the compressor and saving energy.

[0031] Embodiment 2

[0032] Based on Example 1, see Figure 3 shown.

[0033] A mixing mechanism 7 is provided on the upper tower 1a, and a mixing mechanism 7 is also provided in the lower tower 1b, the upper tower 2a and the lower tower 2b. A filter 8 is provided between the lower tower 1b and the lower tower 2b. In the process of treating the catalyst powder, a rotating cleaning brush 11 is used to clean the filter cartridge 73 to prevent the filter cartridge 73 from being blocked. However, some catalyst powder will penetrate into the filter cartridge 73. As the cleaning brush 11 rotates, some of the penetrated catalyst powder will be pressed into the outlet pipes of the lower tower 1b and the lower tower 2b. Therefore, a filter 8 is provided on the carbon dioxide pipeline entering the third stage inlet of the compressor, which not only avoids the damage of the desulfurization catalyst powder to the compressor, but also prolongs the service life of the filter element of the filter 8.

[0034] The mixing mechanism 7 includes a fixed plate 71 and a filter plate 72 fixedly connected to the interior of the upper tower 1a, and a filter cartridge 73 arranged on the outlet pipe of the upper tower 1a. A motor 74 is fixedly connected to the top of the fixed plate 71. The motor 74 is electrically connected to an external power supply and is controlled by an external control program. A rotating shaft 75 is fixedly connected to the output end of the motor 74. One end of the rotating shaft 75 passes through the fixed plate 71 and the filter plate 72 in sequence and extends to the bottom of the filter plate 72. A mixing plate 76 is fixedly connected to the rotating shaft 75. A funnel 77 is fixedly connected to the bottom of the filter plate 72. One end of the funnel 77 passes through the upper tower 1a and extends to the outside of the upper tower 1a.

[0035] One end of the outlet pipe of the upper tower 1a passes through the funnel 77 and extends to the inside of the funnel 77, and one end of the inlet pipe of the upper tower 1a passes through the fixed plate 71 and extends to the bottom of the fixed plate 71. During the desulfurization process, the motor 74 is turned on, and then the motor 74 drives the rotating shaft 75, the scraper 9 and the fixed frame 10 to rotate, so that the reaction of the catalyst and sulfur can be improved by the rotating mixing plate 76. At the same time, the rotation of the mixing plate 76 makes the catalyst powder fall to the bottom layer, so that under the action of the filter plate 72, the catalyst powder falls into the funnel 77, and the rotating scraper 9 can facilitate the passage of the catalyst powder. Afterwards, the preliminarily treated carbon dioxide gas will also pass through the filter plate 72, and then pass through the filter cartridge 73 to enter the outlet pipe portion of the upper tower 1a (or the outlet pipe portion of the upper tower 2a), and then enter the lower tower 1b (or the lower tower 2b), and the carbon dioxide gas is further treated for a second time using the above steps. Afterwards, the carbon dioxide gas is discharged from the outlet pipe portion of the lower tower 1b (or the outlet pipe portion of the lower tower 2b).

[0036] Embodiment 3

[0037] Based on Example 1, see Figure 3 and Figure 4 Shown

[0038] A scraper plate 9 is fixedly connected to the outer surface of the rotating shaft 75 , and the bottom of the scraper plate 9 is in contact with the bottom of the filter plate 72 .

[0039] A fixing frame 10 is fixedly connected to the outer surface of the rotating shaft 75, and a cleaning brush 11 is fixedly connected to the fixing frame 10. The cleaning brush 11 is fitted with the filter cartridge 73, and the fixing frame 10 is fitted with the filter plate 72. When the carbon dioxide gas enters the lower tower 1b (or the lower tower 2b), the filter cartridge 73 is cleaned by the rotating cleaning brush 11 in the process of treating the catalyst powder to prevent the filter cartridge 73 from being blocked. However, some catalyst powder will penetrate into the filter cartridge 73. As the cleaning brush 11 rotates, some of the infiltrated catalyst powder will be pressed into the outlet pipe of the lower tower 1b (or the lower tower 2b). Therefore, a filter 8 is set on the carbon dioxide pipeline entering the third stage inlet of the compressor to avoid damage to the compressor by the desulfurization catalyst powder.

[0040] The fixing plate 71 is located above the feed pipe 5 , and the filter plate 72 is located below the discharge pipe 6 .

[0041] The first conduit 31 , the second conduit 32 , the third conduit 33 and the fourth conduit 34 are all provided with control valves, and an end cap is provided on one end of the funnel 77 .

[0042] Embodiment 4

[0043] In combination with Embodiment 1, Embodiment 2 and Embodiment 3, see Figure 1-4 shown.

[0044] By setting up two desulfurization towers, sulfur in carbon dioxide gas is removed, which protects the subsequent dehydrogenation catalyst and greatly extends the service life of the dehydrogenation catalyst. Dehydrogenation catalysts are usually precious metals with large investments, and extending their service life saves a lot of investment. The parallel and series structure of the desulfurization tower also makes the operation more flexible, easily coping with fluctuations in the sulfur content of carbon dioxide.

[0045] The working principle of the present invention is as follows: the upper tower 1a and the upper tower 2a are equipped with activated carbon, the lower tower 1b and the lower tower 2b are equipped with zinc oxide, the sulfur in the carbon dioxide gas is absorbed and converted by the catalyst, and the whole desulfurization tower is connected in parallel or in series through the connection mode of the first conduit 31, the second conduit 32, the third conduit 33 and the fourth conduit 34, and a differential pressure gauge 4 is provided to measure the inlet and outlet pressure difference of the desulfurization tower. When the pressure difference of the upper tower or the lower tower of one desulfurization tower increases to a certain extent, the other desulfurization tower is switched to work, and the desulfurization tower with increased pressure difference is cut out of the system to replace the catalyst. In the process of desulfurization, the motor 74 is turned on, and then the motor 74 drives the rotating shaft 75, the scraper 9 and the fixing frame 10 to rotate, so that the reaction between the catalyst and the sulfur can be improved by the rotating mixing plate 76, and at the same time, the catalyst powder is dropped to the bottom layer by the rotation of the mixing plate 76, so that the catalyst powder falls into the funnel 77 under the action of the filter plate 72, and the rotating scraper 9 can facilitate the passage of the catalyst powder. Afterwards, the preliminarily treated carbon dioxide gas will also pass through the filter plate 72, and then enter the outlet pipe of the upper tower 1a (or the outlet pipe of the upper tower 2a) through the filter cartridge 73, and then enter the lower tower 1b (or the lower tower 2b), and the carbon dioxide gas is further treated by the above steps, and then the carbon dioxide gas is discharged from the outlet pipe of the lower tower 1b (or the outlet pipe of the lower tower 2b). When the carbon dioxide gas enters the lower tower 1b (or the lower tower 2b), in the process of treating the catalyst powder, the filter cartridge 73 is cleaned by the rotating cleaning brush 11 to prevent the filter cartridge 73 from being blocked, but some catalyst powder will still penetrate into the filter cartridge 73. As the cleaning brush 11 rotates, some of the infiltrated catalyst powder will be pressed into the outlet pipe of the lower tower 1b (or the lower tower 2b). Therefore, the carbon dioxide pipeline entering the third section of the compressor is provided with a filter 8 to avoid the desulfurization catalyst powder from damaging the compressor.

[0046] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A carbon dioxide desulfurization system for a urea plant, characterized in that: The invention comprises a first desulfurization tower (1) and a second desulfurization tower (2), wherein the first desulfurization tower (1) is composed of an upper tower 1 (1a) and a lower tower 1 (1b) which are fixedly installed up and down, and the second desulfurization tower (2) is composed of an upper tower 2 (2a) and a lower tower 2 (2b) which are fixedly installed up and down; A connecting mechanism (3) is arranged between the first desulfurization tower (1) and the second desulfurization tower (2), and the connecting mechanism (3) is used to cope with fluctuations in the sulfur content of carbon dioxide.

2. A urea device carbon dioxide desulfurization system according to claim 1, characterized in that: The connecting mechanism (3) comprises a first conduit (31), a second conduit (32), a third conduit (33) and a fourth conduit (34); the first conduit (31) is arranged between the inlet pipe of the upper tower one (1a) and the inlet pipe of the lower tower two (2b); the second conduit (32) is arranged between the outlet pipe of the upper tower one (1a) and the inlet pipe of the lower tower two (2b); the third conduit (33) is arranged between the inlet pipe of the upper tower two (2a) and the inlet pipe of the lower tower one (1b); and the fourth conduit (34) is arranged between the outlet pipe of the upper tower two (2a) and the inlet pipe of the lower tower one (1b).

3. The carbon dioxide desulfurization system of a urea device according to claim 1, characterized in that: The upper tower 1 (1a), the lower tower 1 (1b), the upper tower 2 (2a) and the lower tower 2 (2b) are all provided with a differential pressure gauge (4), a feed pipe (5) and a discharge pipe (6).

4. The carbon dioxide desulfurization system of a urea device according to claim 2, characterized in that: The upper tower 1 (1a) is provided with a mixing mechanism (7), and a filter (8) is provided between the lower tower 1 (1b) and the lower tower 2 (2b).

5. A carbon dioxide desulfurization system for a urea plant according to claim 4, characterized in that: The mixing mechanism (7) comprises a fixed plate (71) and a filter plate (72) fixedly connected to the interior of the upper tower (1a), and a filter cartridge (73) arranged on the outlet pipe of the upper tower (1a); a motor (74) is fixedly connected to the top of the fixed plate (71); a rotating shaft (75) is fixedly connected to the output end of the motor (74); one end of the rotating shaft (75) passes through the fixed plate (71) and the filter plate (72) in sequence and extends to the bottom of the filter plate (72); a mixing plate (76) is fixedly connected to the rotating shaft (75); a funnel (77) is fixedly connected to the bottom of the filter plate (72); one end of the funnel (77) passes through the upper tower (1a) and extends to the outside of the upper tower (1a).

6. A urea plant carbon dioxide desulfurization system according to claim 5, characterized in that: One end of the outlet pipe of the upper tower (1a) passes through the funnel (77) and extends to the interior of the funnel (77), and one end of the inlet pipe of the upper tower (1a) passes through the fixed plate (71) and extends to the bottom of the fixed plate (71).

7. The carbon dioxide desulfurization system of a urea device according to claim 5, characterized in that: A scraper (9) is fixedly connected to the outer surface of the rotating shaft (75), and the bottom of the scraper (9) is in contact with the bottom of the filter plate (72).

8. The carbon dioxide desulfurization system of a urea device according to claim 5, characterized in that: A fixing frame (10) is fixedly connected to the outer surface of the rotating shaft (75), a cleaning brush (11) is fixedly connected to the fixing frame (10), the cleaning brush (11) is fitted with the filter cartridge (73), and the fixing frame (10) is fitted with the filter plate (72).

9. The carbon dioxide desulfurization system of a urea plant according to claim 5, characterized in that: The fixing plate (71) is located above the feed pipe (5), and the filter plate (72) is located below the discharge pipe (6).

10. A carbon dioxide desulfurization system for a urea plant according to claim 5, characterized in that: The first conduit (31), the second conduit (32), the third conduit (33) and the fourth conduit (34) are all provided with control valves, and an end cap is provided on one end of the funnel (77).

Images